Thermoplastic compression is a technique of pure titanium microstructure enhancement for biomedical applications

Thermoplastic compression is a technique of pure titanium microstructure enhancement for biomedical applications | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Thermoplastic compression is a technique of pure titanium microstructure enhancement for biomedical applications Jakub Bańczerowski, Marek Pawlikowski, Tomasz Płociński, Andrzej Zagórski, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3323590/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Pure titanium due to its high corrosion resistance, low stiffness and good mechanical properties is commonly used in medicine for orthopaedic applications. However, its material properties can be further enhanced to better fulfil the role of the biocompatible material. The thermoplastic deformation in heightened temperature is proposed as a method for microstructure improvement. Titanium samples were compressed in different temperatures and strain rates in order to determine the best conditions for grain fragmentation – the main factor responsible for strength and hardness increase. The thermoplastic stress-strain curves were registered. Then microstructure observations and electron backscatter analysis were performed on the chosen samples. Finally, mechanical response of the previously deformed material was obtained in room temperature compression tests. A significant grain fragmentation was recorded for the material deformed in 400 °C, at 0.1/s and 1/s strain rates. Desirable results were also noticed for the deformation performed at 500-600 °C. However, high temperatures (700-800 °C) and strain rates (10/s) resulted in dynamic recrystallization, causing undesirable grain growth. An increase in hardness was observed in all cases, with higher values recorded in lower deformation temperatures. Room temperature compression tests revealed slight increase of ductility. Biological sciences/Biotechnology Physical sciences/Materials science Titanium EBSD microstructure grain refinement thermoplastic forming Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Highlights Pure titanium microstructure was severely refined with use of thermoplastic deformation. The preferable conditions for the grain refinement were determined: strain rate should be between 0.1/s and 1/s and temperature between 500 °C to 600 °C. The conditions causing dynamic recrystallization, and therefore undesirable grain growth, were determined – strain rate around 10/s along with temperature above 700 °C. The influence of the thermoplastic deformation on the hardness and yield point is presented. 1. Introduction Pure titanium is a material widely used in biomedical engineering [1], [2]. The basic advantages of this material are high corrosion resistance, biocompatibility , high hardness, suitable osseointegration and good strength properties [2], [3]. However, those are not sufficient for the manufacturing of highly loaded implants like hip joint or knee joint endoprostheses, where Ti6Al4V alloy is still commonly used, even despite a harmful influence of Al and V ions on human tissue [4]. Therefore, the material strengthening is paramount. Previous research [5] indicates that one of the best ways to strengthen the material is by its grain size reduction (according to Hall-Petch theorem) [6]–[8]. Material strengthening is also dependent on the processes of work hardening [9], [10], dislocation evolution [11], or twinning [10], [12], [13]. It can be achieved by plastic or thermoplastic deformation. One of the most popular ways to do it, is reduction of grain size in room temperature by one of the severe plastic deformation methods (SPD) [14]–[17]. However, the disadvantage of methods such as equal-channel angular pressing (ECAP) or high pressure torsion (HPT) is relatively small size of the final product, which severely hampers their use for production of larger implants like hip-joint endoprostheses [15]. Strengthening the material can be obtained also by other means i.e. by thermoplastic deformation in high temperatures (400 - 800 °C) [18], [19]. Commercially pure titanium at room temperature has poor formability and limited ductility, therefore in order to improve this parameter it is necessary to perform deformation at higher temperatures [20]. While undertaking thermoplastic deformation process it is imperative to understand that it is accompanied by the various metallurgical phenomena such as work hardening, dynamic recrystallization (DRX), dynamic recovery (DRV) [21] and different deformation mechanisms [20]. A number of works can be found in the literature about mechanisms of thermoplastic deformation of the commercially pure (CP) titanium. Baral et al. [22] conducted various deformation tests on the CP-Ti grade 2 titanium cut from hot-rolled plate. The focus of their studies was on identification of the plastic deformation mechanisms occurring during the process. The study states that the most common deformation mechanism was twinning. Similar work was conducted by Nixon et al. [23], where he confirmed that material hardening was associated with twinning. However, twinning is not always a dominating mechanism, especially when we are dealing with high strains [24], [25]. Becker and Pantleon [26] focused on work hardening behavior of CP-Ti under different, low strain rates (0.0002/s – 0.67/s). They conclude that there is a linear decrease of the work hardening rate with increasing true stress. However, their tests were performed in the room temperature. Gurao et al. [27] performed similar research focusing on the titanium deformation behavior at extreme strain rates in room temperature. Their work focus on the dependency between crystal orientations and deformation mechanisms. In Zeng’s work [28] Grade 2 titanium was compressed at elevated temperatures (673 K – 973 K) and under different strain rates (0.001 to 1 s -1 ) to observe microstructure evolution under those conditions. The authors have observed an increased grain refinement along with overall sample height reduction. The grain size increased with the deformation temperature indicating process of DRX. However, the majority of those studies while focusing on the deformation mechanisms, does not take into account how grain fragmentation actually influenced the strength of the material. In recent years there is noticeable lack of works focusing on the pure α-titanium, therefore there is need to supplement this knowledge. This work is an attempt to determine how thermoplastic deformation exactly influenced material properties of the CP titanium. In order to supplement the deformation experiment data and material observations, hardness measurement and compression test were also performed. Moreover, to complement other researchers work, we decided to broaden the spectrum of temperatures and strain rates used during the tests. Finally, in many thermoplastic deformation publications the matter of the high total strain is often neglected. This factor is however of the extreme importance as many SPD researchers indicate [4], [15], [17], [29]. Thus, we decided to deform our samples until the height reduction of 60% was reached, which corresponds with the true strain equal 0.92. 2. Materials and methods The material used in the experiment was CP Ti Grade 2, which chemical composition is the table 1. Tab. 1.: Chemical composition of the Grade 2 titanium according to EN 10204-3.1 + PED 2014/68/EU Chemical Composition (wt. %) Al V C O N H Fe Ti - - 0.013 0.143 0.013 <0.0006 0.13 Remainder The samples were cut from the annealed Ø10 rod into 12 mm high cylinders. Then, they were compressed under various temperatures and strain rates in the Gleeble 3800 thermoplastic simulator- the equipment for dynamic thermal-mechanical testing of materials and physical simulation of processes. Compression was stopped at 0.92 true strain. The full extent of the experiment is covered in the table 2. In order to limit the influence of the friction on the uneven deformation of samples, graphite tantalum washers and graphite based grease were introduced between the faces of the samples and on the surfaces of the tools. Two K-type thermocouples located on the cylindrical surface of the sample were used to register and control changes in temperature. The samples were heated by the resistance method using anvils. In order to limit the influence of scale on the determined value, the tests were performed in a vacuum. Tab. 2: The thermoplastic compression tests plan Sample number Temperature Strain rate [ Number of repetitions p1 400°C (673 K) 0.01 4 p2 0.1 3 p3 1 3 p4 10 4 p17 500° C (773 K) 0.01 2 p18 0.1 2 p19 1 2 p20 10 3 p13 600° C (873 K) 0.01 2 p14 0.1 2 p15 1 4 p16 10 4 p5 700° C (973 K) 0.01 4 p6 0.1 3 p7 1 3 p8 10 3 p9 800° C (1073 K) 0.01 3 p10 0.1 3 p11 1 3 p12 10 3 After the experiment in order to determine grain size and grain size distribution the microstructure observations were performed using scanning electron microscope (SEM) Hitachi SU70 along with electron backscatter diffraction (EBSD) analysis made by Bruker. The investigated areas were taken from the central part of the samples. Proper preparation of the samples is of the great importance. In order to maintain the post-experimental structure, samples were cut using the low speed diamond saw. Then they were mechanically polished and finally ion polished. To obtain stress free surface on the sample the system Hitachi IM4000 was applied on the cross section of the sample. Argon ion broad beam is one of the best technique to prepare proper surface for the analysis. The EBSD data were performed at 20kV accelerating voltage and the 100 nm step size and 1000 times magnification. The data were analysed with Bruker software to determine the grain size distribution and provide EBSD maps. For the article the inverse pole figure colouring was chosen. The EBSD analysis did not revealed significant texture in the analysed samples. Due to severe plastic deformation, some maps consist low rate of resolved patterns, what is typical for this technique. Changes in the strength of the material have been checked by performing compression strength tests using INSTRON 8802 under the 1/min strain rate. Samples were deformed until maximum machine load was reached (250 kN). To supplement those results Vickers microhardness tests were also performed. 3. Results and discussion A simple dependency was observed: with an increase in temperature, the material required less strength to become plastic. The higher strain rates were also responsible for the increase in stresses. In the most cases (fig. 1-3), especially at the temperature range 600 – 800 °C, the curves shape was similar and typical for the plastically deformed metals [30]. Several cases represent an interesting behaviour – the stress-strain curve contains clearly visible maximum turning point (“hunch”) like curve 400 °C in 10 s -1 (fig. 1a) or curve 500 °C in 10 s -1 (fig. 1b). It indicates the existence of three-stage work hardening [20], [25], [30]. In the phase I, work hardening is the dominant mechanism – the stresses rapidly increase. In the phase II, the dynamic recovery (DRV) influence is more significant and the mechanism of dynamic recrystallization (DRX) begins to appear. The phase III is characterized by the drop in the stresses, caused by the domination of the DRX phenomenon [30]. The curves are also characterized by their serrated character, more prevalent at the higher strain rates. Such phenomenon, known as the Portevin-Le Chatelier (PLC) effect, can be often observed in metals, however the mechanisms behind it are varied [31], [32]. In the case of the pure α-titanium this is most likely a result of the mobile dislocations being blocked by the solute atoms like C or N. After overcoming an obstacle, the dislocation jumps to the next one resulting in the effect visible on the curve as serration [33]. For the tests conducted in higher temperatures (600 – 800 °C, fig. 2) we can observe slightly different behaviour. We registered only two phases: after the rapid and short work hardening we can see the plastic flow. Similar behaviour was observed by Nemat-Nasser, or Zeng [20], [34], where two-stage work hardening was found in the case of titanium deformed at higher temperatures. For lower strain rates (fig. 2) thermal softening indicated by the curve drop can be also observed. The strain – stress curves apart from providing valuable information about thermomechanical processes occurring in the material, served as a tool for the sample selection for microstructure analysis. For the SEM observation and EBSD analysis all samples deformed in 400 °C were selected due to their distinctive curve shape as well as the fact that samples deformed in this temperature were rarely described in literature. For the comparison, samples from the other end of the tests spectrum was also analysed: 800 °C for the minimum and maximum strain rates (0.01 s -1 and 10 s -1 ). For the reference, original, undeformed sample was also observed. Original sample microstructure observation revealed equiaxed grains. (Fig 3a). The EBSD analysis performed for the original sample indicates existence of the grains of homogenous size. The average size of the grain was detected as 6.06 µm and median size is 5.22 µm (fig. 4a). At the 400 °C temperature and the low strain rate (0.01/s), we can observe grain size reduction and deformation. The grains are elongated. Significant amount of grains were fragmented, and the average and median grain size were also lower being equal respectively 4.93 µm and 3.79 µm (fig. 3b). In the case of 400 °C and 0.1/s sample we can see very significant grain size reduction. The recorded average and median grain sizes were equal 2.62 µm and 1.61 µm respectively (fig 3c, 4b). We can observe almost identical grain distribution for the 400 °C, 1/s sample as in the previous one. But this value could be even smaller because we could observe significant amount of unresolved analysis points what is related to stronger plastic deformation and higher density of defects in the material. The higher strain rate does not seem to significantly improve grain fragmentation but the grains looks more deformed and elongated. Between the elongated grains we could observe fragmentation of the grains which is below the resolution of the system (fig. 3d). Average grain size equals 2.1 µm, while median grain size is 1.43 µm (fig. 4c). For the highest strain rate in 400 °C we recorded unusual grain distribution. During this thermoplastic test DRX occurred due to combination of temperature and high strain rate causing grain growth. Grain size distribution is similar to the original sample apart from the larger amount of small sized grains. The grain size distribution looks more like a bimodal. We could observe significant number of bigger grains with visible slip bands, and high number of small grains between the bigger ones (fig. 3e). Avg. grain size is 5.04 µm while median size is 3.61 µm (fig. 4d). In the case of the samples deformed in highest temperature i.e.: 800 °C we clearly can see that the high temperature caused grain growth, which effect was not eliminated even by high strain rate. For the 800 °C, 0.01/s sample we can see a significant increase in the grain size, with the average size: 15.5 µm and median being 13.5 µm (fig. 5a, 6a). For the 10/s strain rate we still could observe an increase in the grain size, although not such drastic as in previous example. The registered values of average and median grain size are: 11.1 µm and 8.94 µm (fig 5b, 6b). Comparative compression strength tests were made in order to monitor changes in material strength. Tests were performed on the INSTRON 8802 machine with strain rate equal to 1/min. The samples were deformed until 250 kN of load was reached. Specimens were cut from the samples previously compressed during thermoplastic experiment. Their dimensions were 12 mm in diameter and 5.5 mm in height. The changes in the sample length during compression were monitored with use of the extensometer. The stress-strain curves registered as a result of the measurement were used to determine the yield point of each sample. Original material during compression in the room temperature yields at around 900 MPa (fig. 7). Similar response of the material was reported by Soares and Hokka [35], where alpha titanium compressed with the strain rate 1/s yielded at 700-800 MPa. In this case, for the specimens previously deformed under 400° C, yield point is around 600 MPa for the 10/s strain rate and 1380 MPa for the 0.01/s strain rate indicating strengthening of the material (fig. 7a). For both 0.1/s and 1/s material yields around 700 MPa (fig. 7a). In the case of “500 °C” set we can observe slight increase of the yield point in relation to the strain rate. For 0.01/s we can report 913 MPa, for 0.1/s – 980 MPa, for 1/s 1100 MPa is noted, and for 10/s, 1250 MPa is reported (fig. 7b). In the “600° C” set, yield point can be observed at around 800-850 MPa for all but 10/s strain rates. This one yields at 1000 MPa (fig. 7c). Specimens deformed at the 700° C show similar behaviour as those deformed at 600° C with the only difference in the values of the Yield point. For the 10/s sample it is around 1000 MPa, for the rest – 600-800 MPa (fig. 7d). Interestingly, for the “800°C” set we have 800 MPa yield point for all samples (fig. 7e). It is worth noticing changes of the work hardening behaviour of the specimens. With an increase of the temperature, the yield point becomes less obvious and material deforms more plastically. The influence of the strain rate is also suppressed by the temperature influence (fig. 7d, e). This can be attributed to the behaviour of dislocation slip in samples deformed at higher temperatures [36]. Hardness measurements were performed on a HV 0.2 scale. The load was equal 1.961 N with the hold time equal 5 seconds. Six measurements were taken on each sample to provide statistically reliable results. The mean hardness HV 0.2 for undeformed Grade 2 titanium is 200.4 – which is characteristic for this material [37]. The mean hardness values are presented alongside the yield points of the deformed titanium (fig. 8). In all cases an improvement in hardness is visible. For the samples deformed in 400 °C we can observe an average increase by 65 points, for 500 °C by 74 points, for 600 °C - 53 points, 700 °C - 43 points, and for 800 °C – 36 points. The most significant hardness increase was observed for temperature range 400 – 600 °C. For the highest temperatures the grain growth overcame the process of grain fragmentation, causing an increase in grain size and thus lowering hardness values [38]. Lower hardness values could also be attributed to dislocation systems created at high temperatures [36], [39]. One of the significant factors influencing the hardness of the titanium is grain size. In the case of titanium deformed at 400 °C significant grain reduction has been achieved. For the 800 °C an increase in hardness was also registered, but not as noticeable as for lower temperature (fig. 9). This observations clearly indicate strong influence of multiple factors on the acquired results: dislocation density, microstructure texture, grain orientation etc. [40]. 4. Summary and conclusions Thermoplastic deformation of the pure titanium has been performed successfully, resulting in significant grain size reduction and meaningful changes in the material properties. The most desirable changes were noted for the deformation performed at 400 °C, with strain rates 0.1/s and 1/s. As indicated in previous report [5], very desirable grain reduction was also achieved at 600 °C, so we can safely assume that temperature 500 °C is also viable for this process. The DRX was noted for the deformation at 400 °C and 10/s strain rate, causing grain growth. Thus, we can conclude that this strain rate is too high. Both 0.1/s and 1/s present good findings, however in the case of 1/s there is a lot of unindexed points, which indicates high dislocation density and high grain fragmentation, which in turn greatly improves fibroblast cells colonization [41]–[43]. The temperature 800 °C is definitely too high for the purpose of grain fragmentation. Stress-strain graphs, microstructure observations, EBSD analysis, and strength test indicate that grain growth due to high temperature suppresses grain fragmentation caused by high strain rates. The experimental results also indicate that 700 °C temperature might be undesirable. We observed an increase in hardness values for all cases in comparison to the original sample. The grain size however seems to be only one of the factors influencing this property. The literature studies point to the dislocation density as one of the most meaningful factors influencing hardness [39]. The temperature seems to have an effect on the hardness, but strain rate influence seems to be negligible. Increase in hardness is beneficial from the biomedical point of view due to the improved resistance against wear and corrosion [44], [45]. This interesting findings not only highlight the viability of thermomechanical processing as a tool for grain fragmentation but also point at new research opportunities: there is necessity in determination how dislocation density, microstructure texture and grain orientation influence the hardness and plasticity of the titanium. Declarations Data availability The dataset used and/or analysed during the current study will be made available by the corresponding author on reasonable request. References N. Soro, L. Brassart, Y. Chen, M. Veidt, H. Attar, and M. S. Dargusch, “Finite element analysis of porous commercially pure titanium for biomedical implant application,” Mater. Sci. Eng. 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Liu, “A study on the hardness variation of α- and β-pure titanium with different grain sizes,” Mater. Sci. Eng. A , vol. 398, no. 1–2, pp. 93–98, May 2005, doi: 10.1016/j.msea.2005.03.004. D. M. Norfleet, D. M. Dimiduk, S. J. Polasik, M. D. Uchic, and M. J. Mills, “Dislocation structures and their relationship to strength in deformed nickel microcrystals,” Acta Mater. , vol. 56, no. 13, pp. 2988–3001, Aug. 2008, doi: 10.1016/j.actamat.2008.02.046. A. S. Gornakova et al. , “Effect of composition, annealing temperature, and high pressure torsion on structure and hardness of Ti–V and Ti–V–Al alloys,” J. Appl. Phys. , vol. 125, no. 8, p. 082522, Feb. 2019, doi: 10.1063/1.5053937. R. Z. Valiev et al. , “Nanostructured Titanium for Biomedical Applications,” Adv. Eng. Mater. , vol. 10, no. 8, pp. B15–B17, Aug. 2008, doi: 10.1002/adem.200800026. H. Mora-Sanchez, I. Sabirov, M. A. Monclus, E. Matykina, and J. M. Molina-Aldareguia, “Ultra-fine grained pure Titanium for biomedical applications,” Mater. Technol. , vol. 31, no. 13, pp. 756–771, Nov. 2016, doi: 10.1080/10667857.2016.1238131. S. Bagherifard, R. Ghelichi, A. Khademhosseini, and M. Guagliano, “Cell Response to Nanocrystallized Metallic Substrates Obtained through Severe Plastic Deformation,” ACS Appl. Mater. Interfaces , vol. 6, no. 11, pp. 7963–7985, Jun. 2014, doi: 10.1021/am501119k. A. M. Khorasani, M. Goldberg, E. H. Doeven, and G. Littlefair, “Titanium in Biomedical Applications—Properties and Fabrication: A Review,” J. Biomater. Tissue Eng. , vol. 5, no. 8, pp. 593–619, Aug. 2015, doi: 10.1166/jbt.2015.1361. M. Niinomi, “Mechanical biocompatibilities of titanium alloys for biomedical applications,” J. Mech. Behav. Biomed. Mater. , vol. 1, no. 1, pp. 30–42, Jan. 2008, doi: 10.1016/j.jmbbm.2007.07.001. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3323590","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":231494931,"identity":"afc2eae5-553f-4acc-a27a-5d14f29ea99a","order_by":0,"name":"Jakub Bańczerowski","email":"data:image/png;base64,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","orcid":"","institution":"Warsaw University of Technology","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Jakub","middleName":"","lastName":"Bańczerowski","suffix":""},{"id":231494935,"identity":"cc123ec7-16ee-451c-991e-a210374921df","order_by":1,"name":"Marek Pawlikowski","email":"","orcid":"","institution":"Warsaw University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Marek","middleName":"","lastName":"Pawlikowski","suffix":""},{"id":231494937,"identity":"3c120dea-94b2-4404-a21e-1b9090223f2d","order_by":2,"name":"Tomasz Płociński","email":"","orcid":"","institution":"Warsaw University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Tomasz","middleName":"","lastName":"Płociński","suffix":""},{"id":231494939,"identity":"6a78c084-0a29-4d4d-9ca2-513eb5529352","order_by":3,"name":"Andrzej Zagórski","email":"","orcid":"","institution":"Warsaw University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Andrzej","middleName":"","lastName":"Zagórski","suffix":""},{"id":231494941,"identity":"bf6c91bc-a7be-475a-8da1-aa95be9e07ca","order_by":4,"name":"Sylwester Sawicki","email":"","orcid":"","institution":"Czestochowa University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Sylwester","middleName":"","lastName":"Sawicki","suffix":""},{"id":231494943,"identity":"f40bd38f-942b-4f93-8d86-b5cf6f7156e6","order_by":5,"name":"Roman Gieleta","email":"","orcid":"","institution":"Military University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Roman","middleName":"","lastName":"Gieleta","suffix":""}],"badges":[],"createdAt":"2023-09-04 08:44:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3323590/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3323590/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":43012047,"identity":"3f5f085e-22e6-462a-8a6b-29b142c3d298","added_by":"auto","created_at":"2023-09-12 14:43:17","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":62358,"visible":true,"origin":"","legend":"\u003cp\u003eStress-strain graphs for the compression at 400°C and 500°C at various strain rates\u003c/p\u003e","description":"","filename":"F1.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/a095c61814d204990b5f8f9a.png"},{"id":43012050,"identity":"353dadff-6903-4ace-bba5-15e42d0fdcff","added_by":"auto","created_at":"2023-09-12 14:43:17","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":66672,"visible":true,"origin":"","legend":"\u003cp\u003eStress-strain graphs for the compression at: a) 600 °C, b) 700 °C, c) 800°C at various strain rates\u003c/p\u003e","description":"","filename":"F2.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/e85c0868f09d3f185b1bef92.png"},{"id":43012053,"identity":"5fc51e5f-8c30-43e9-9f96-89db421fa7f0","added_by":"auto","created_at":"2023-09-12 14:43:17","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":992850,"visible":true,"origin":"","legend":"\u003cp\u003ea) EBSD image of the original, undeformed sample, b) deformed in 400° C, under 0.01/s strain rate, c) deformed in 400° C, under 0.1/s strain rate, d) deformed in 400° C, under 1/s strain rate, e) deformed in 400° C, under 10/s strain rate.\u003c/p\u003e","description":"","filename":"F3.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/09088eec1eb673e85d17c9ec.png"},{"id":43012051,"identity":"36047bc3-3589-4b3c-974a-fefd4a3a735a","added_by":"auto","created_at":"2023-09-12 14:43:17","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":62022,"visible":true,"origin":"","legend":"\u003cp\u003eGrain size distribution of the original, undeformed sample (blue) and of the titanium sample deformed (yellow) in 400° C, under: a) 0.01/s strain rate, b) 0.1/s strain rate, c) 1/s strain rate, d) 10/s strain rate.\u003c/p\u003e","description":"","filename":"F4.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/504b53b724d3243b86c8d3db.png"},{"id":43012054,"identity":"4a71d119-e05a-4a74-aaa2-8c14a96952c4","added_by":"auto","created_at":"2023-09-12 14:43:17","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":621975,"visible":true,"origin":"","legend":"\u003cp\u003eEBSD image of the titanium deformed in 800° C: a) under 0.01/s strain rate, b) under 10/s strain rate\u003c/p\u003e","description":"","filename":"F5.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/46b28e850f25f50acc239eff.png"},{"id":43013228,"identity":"559e00d7-9766-401b-9d2b-aa69027d6184","added_by":"auto","created_at":"2023-09-12 14:51:17","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":45800,"visible":true,"origin":"","legend":"\u003cp\u003eGrain size distribution of the original, undeformed sample (blue) and of the titanium sample deformed (orange) in 800° C, under: a) 0.01 s-1 strain rate, b) 10 s-1 strain rate\u003c/p\u003e","description":"","filename":"F6.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/962a8a9586080015168a26a7.png"},{"id":43013227,"identity":"2d2ce41b-6512-4005-8041-847b10ee8534","added_by":"auto","created_at":"2023-09-12 14:51:17","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":124018,"visible":true,"origin":"","legend":"\u003cp\u003eStress – strain graph for the samples deformed previously at: a) 400 °C, b) 500 °C, c) 600 °C, d) 700 °C, e) 800°C\u003c/p\u003e","description":"","filename":"F7.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/ec147633897cfd98612479f4.png"},{"id":43012056,"identity":"0490d029-4151-499b-8090-438150b71208","added_by":"auto","created_at":"2023-09-12 14:43:17","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":100101,"visible":true,"origin":"","legend":"\u003cp\u003eYield point and hardness HV 0.2 of the titanium deformed at: a) 400 °C, b) 500 °C, c) 600 °C, d) 700 °C, e) 800°C\u003c/p\u003e","description":"","filename":"F8.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/27fb771a92cf381faccb552b.png"},{"id":43013229,"identity":"418b24d3-b07d-4247-93e3-2059b6e174ad","added_by":"auto","created_at":"2023-09-12 14:51:17","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":27328,"visible":true,"origin":"","legend":"\u003cp\u003eRelation between grain size and hardness of the deformed titanium.\u003c/p\u003e","description":"","filename":"F9.png","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/19747bb960d236cc3f0179c3.png"},{"id":46717514,"identity":"2bd1e933-ba2c-49d6-ad6f-0ffdb3413132","added_by":"auto","created_at":"2023-11-19 06:22:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2207664,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3323590/v1/c4cf7bf6-c7cb-4b57-a3ac-e227059dd7c0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Thermoplastic compression is a technique of pure titanium microstructure enhancement for biomedical applications","fulltext":[{"header":"Highlights","content":"\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003ePure titanium microstructure was severely refined with use of thermoplastic deformation.\u003c/li\u003e\n \u003cli\u003eThe preferable conditions for the grain refinement were determined: strain rate should be between 0.1/s and 1/s and temperature between 500 \u0026deg;C to 600 \u0026deg;C.\u003c/li\u003e\n \u003cli\u003eThe conditions causing dynamic recrystallization, and therefore undesirable grain growth, were determined \u0026ndash; strain rate around 10/s along with temperature above 700 \u0026deg;C.\u003c/li\u003e\n \u003cli\u003eThe influence of the thermoplastic deformation on the hardness and yield point is presented.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"1. Introduction","content":"\u003cp\u003ePure titanium is a material widely used in biomedical engineering\u0026nbsp;[1], [2]. The basic advantages of this material are high corrosion resistance, biocompatibility , high hardness, suitable osseointegration and good strength properties\u0026nbsp;[2], [3]. However, those are not sufficient for the manufacturing of highly loaded implants like hip joint or knee joint endoprostheses, where Ti6Al4V alloy is still commonly used, even despite a harmful influence of Al and V ions on human tissue\u0026nbsp;[4].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTherefore, the material strengthening is paramount. Previous research\u0026nbsp;[5]\u0026nbsp;indicates that one of the best ways to strengthen the material is by its grain size reduction (according to Hall-Petch theorem)\u0026nbsp;[6]\u0026ndash;[8]. Material strengthening is also dependent on the processes of work hardening\u0026nbsp;[9], [10], dislocation evolution\u0026nbsp;[11], or twinning\u0026nbsp;[10], [12], [13]. \u0026nbsp;It can be achieved by plastic or thermoplastic deformation. One of the most popular ways to do it, is reduction of grain size in room temperature by one of the severe plastic deformation methods (SPD)\u0026nbsp;[14]\u0026ndash;[17]. However, the disadvantage of methods such as equal-channel angular pressing (ECAP) or high pressure torsion (HPT) is relatively small size of the final product, which severely hampers their use for production of larger implants like hip-joint endoprostheses\u0026nbsp;[15]. Strengthening the material can be obtained also by other means i.e. by thermoplastic deformation in high temperatures (400 - 800 \u0026deg;C)\u0026nbsp;[18], [19]. Commercially pure titanium at room temperature has poor formability and limited ductility, therefore in order to improve this parameter it is necessary to perform deformation at higher temperatures\u0026nbsp;[20].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWhile undertaking thermoplastic deformation process it is imperative to understand that it is accompanied by the various metallurgical phenomena such as work hardening, dynamic recrystallization (DRX), dynamic recovery (DRV)\u0026nbsp;[21]\u0026nbsp;and different deformation mechanisms\u0026nbsp;[20].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA number of works can be found in the literature about mechanisms of thermoplastic deformation of the commercially pure (CP) titanium. \u0026nbsp;Baral et al.\u0026nbsp;[22]\u0026nbsp;conducted various deformation tests on the CP-Ti grade 2 titanium cut from hot-rolled plate. The focus of their studies was on identification of the plastic deformation mechanisms occurring during the process. The study states that the most common deformation mechanism was twinning. Similar work was conducted by Nixon et al.\u0026nbsp;[23], where he confirmed that material hardening was associated with twinning. However, twinning is not always a dominating mechanism, especially when we are dealing with high strains\u0026nbsp;[24], [25]. \u0026nbsp;Becker and Pantleon\u0026nbsp;[26]\u0026nbsp;focused on work hardening behavior of CP-Ti under different, low strain rates (0.0002/s \u0026ndash; 0.67/s). They conclude that there is a linear decrease of the work hardening rate with increasing true stress. However, their tests were performed in the room temperature. Gurao et al.\u0026nbsp;[27]\u0026nbsp;performed similar research focusing on the titanium deformation behavior at extreme strain rates in room temperature. Their work focus on the dependency between crystal orientations and deformation mechanisms. In Zeng\u0026rsquo;s work\u0026nbsp;[28]\u0026nbsp;Grade 2 titanium was compressed at elevated temperatures (673 K \u0026ndash; 973 K) and under different strain rates (0.001 to 1 s\u003csup\u003e-1\u003c/sup\u003e ) to observe microstructure evolution under those conditions. The authors have observed an increased grain refinement along with overall sample height reduction. The grain size increased with the deformation temperature indicating process of DRX.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHowever, the majority of those studies while focusing on the deformation mechanisms, does not take into account how grain fragmentation actually influenced the strength of the material. In recent years there is noticeable lack of works focusing on the pure\u0026nbsp;\u0026alpha;-titanium, therefore there is need to supplement this knowledge. This work is an attempt to determine how thermoplastic deformation exactly influenced material properties of the CP titanium. In order to supplement the deformation experiment data and material observations, hardness measurement and compression test were also performed. Moreover, to complement other researchers work, we decided to broaden the spectrum of temperatures and strain rates used during the tests. Finally, in many thermoplastic deformation publications the matter of the high total strain is often neglected. This factor is however of the extreme importance as many SPD researchers indicate\u0026nbsp;[4], [15], [17], [29]. Thus, we decided to deform our samples until the height reduction of 60% was reached, which corresponds with the true strain equal 0.92.\u0026nbsp;\u003c/p\u003e"},{"header":"2.\tMaterials and methods","content":"\u003cp\u003eThe material used in the experiment was CP Ti Grade 2, which chemical composition is the table 1.\u003c/p\u003e\n\u003cp\u003eTab. \u0026nbsp;1.: Chemical composition of the Grade 2 titanium according to EN 10204-3.1 + PED 2014/68/EU\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"8\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eChemical Composition (wt. %)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAl\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003eV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003eO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003eH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003eFe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.924071082390952%\" valign=\"top\"\u003e\n \u003cp\u003eTi\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e0.013\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e0.143\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e0.013\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.0006\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.439418416801292%\" valign=\"top\"\u003e\n \u003cp\u003e0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.924071082390952%\" valign=\"top\"\u003e\n \u003cp\u003eRemainder\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe samples were cut from the annealed \u0026Oslash;10 rod into 12 mm high cylinders. Then, they were compressed under various temperatures and strain rates in the Gleeble 3800 thermoplastic simulator- the equipment for dynamic thermal-mechanical testing of materials and physical simulation of processes. Compression was stopped at 0.92 true strain. The full extent of the experiment is covered in the table 2. In order to limit the influence of the friction on the uneven deformation of samples, graphite tantalum washers and graphite based grease were introduced between the faces of the samples and on the surfaces of the tools. Two K-type thermocouples located on the cylindrical surface of the sample were used to register and control changes in temperature. The samples were heated by the resistance method using anvils. In order to limit the influence of scale on the determined value, the tests were performed in a vacuum.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTab. \u0026nbsp;2: The thermoplastic compression tests plan\u003c/p\u003e\n\u003cdiv\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"389\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.41025641025641%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSample number\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"32.56410256410256%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTemperature\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eStrain rate [\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eNumber of repetitions\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.41025641025641%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"32.56410256410256%\" rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e400\u0026deg;C (673 K)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.41025641025641%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep17\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"32.56410256410256%\" rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e500\u0026deg; C (773 K)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep18\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep19\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.41025641025641%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep13\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"32.56410256410256%\" rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e600\u0026deg; C (873 K)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep14\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep16\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.41025641025641%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"32.56410256410256%\" rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e700\u0026deg; C (973 K)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"16.41025641025641%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"32.56410256410256%\" rowspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e800\u0026deg; C\u0026nbsp;\u003cbr\u003e\u0026nbsp;(1073 K)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.512820512820515%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep11\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.334600760456272%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"45.247148288973385%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"30.418250950570343%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eAfter the experiment in order to determine grain size and grain size distribution the microstructure observations were performed using scanning electron microscope (SEM) Hitachi SU70 along with electron backscatter diffraction (EBSD) analysis made by Bruker. The investigated areas were taken from the central part of the samples. Proper preparation of the samples is of the great importance. In order to maintain the post-experimental structure, samples were cut using the low speed diamond saw. Then they were mechanically polished and finally ion polished. To obtain stress free surface on the sample the system Hitachi IM4000 was applied on the cross section of the sample. Argon ion broad beam is one of the best technique to prepare proper surface for the analysis. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe EBSD data were performed at 20kV accelerating voltage and the 100 nm step size and 1000 times magnification. The data were analysed with Bruker software to determine the grain size distribution and provide EBSD maps. For the article the inverse pole figure colouring was chosen. The EBSD analysis did not revealed significant texture in the analysed samples. Due to severe plastic deformation, some maps consist low rate of resolved patterns, what is typical for this technique.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eChanges in the strength of the material have been checked by performing compression strength tests using INSTRON 8802 under the 1/min strain rate. Samples were deformed until maximum machine load was reached (250 kN). To supplement those results Vickers microhardness tests were also performed.\u0026nbsp;\u003c/p\u003e"},{"header":"3.\tResults and discussion","content":"\u003cp\u003eA simple dependency was observed: with an increase in temperature, the material required less strength to become plastic. The higher strain rates were also responsible for the increase in stresses. In the most cases (fig. 1-3), especially at the temperature range 600 \u0026ndash; 800 \u0026deg;C, the curves shape was similar and typical for the plastically deformed metals [30]. Several cases represent an interesting behaviour \u0026ndash; the stress-strain curve contains clearly visible maximum turning point (\u0026ldquo;hunch\u0026rdquo;) like curve 400 \u0026deg;C in 10 s\u003csup\u003e-1\u003c/sup\u003e (fig. 1a) or curve 500 \u0026deg;C in 10 s\u003csup\u003e-1 \u003c/sup\u003e(fig. 1b). It indicates the existence of three-stage work hardening [20], [25], [30]. In the phase I, work hardening is the dominant mechanism \u0026ndash; the stresses rapidly increase. In the phase II, the dynamic recovery (DRV) influence is more significant and the mechanism of dynamic recrystallization (DRX) begins to appear. The phase III is characterized by the drop in the stresses, caused by the domination of the \u0026nbsp;DRX phenomenon [30].\u003c/p\u003e\n\u003cp\u003eThe curves are also characterized by their serrated character, more prevalent at the higher strain rates. Such phenomenon, known as the Portevin-Le Chatelier (PLC) effect, can be often observed in metals, however the mechanisms behind it are varied [31], [32]. In the case of the pure \u0026alpha;-titanium this is \u0026nbsp;most likely a result of the mobile dislocations being blocked by the solute atoms like C or N. After overcoming an obstacle, the dislocation jumps to the next one resulting in the effect visible on the curve as serration [33].\u003c/p\u003e\n\u003cp\u003eFor the tests conducted in higher temperatures (600 \u0026ndash; 800 \u0026deg;C, fig. 2) we can observe slightly different behaviour. We registered only two phases: after the rapid and short work hardening we can see the plastic flow. Similar behaviour was observed by Nemat-Nasser, or Zeng [20], [34], where two-stage work hardening was found in the case of titanium deformed at higher temperatures. For lower strain rates (fig. 2) thermal softening indicated by the curve drop can be also observed.\u003c/p\u003e\n\u003cp\u003eThe strain \u0026ndash; stress curves apart from providing valuable information about thermomechanical processes occurring in the material, served as a tool for the sample selection for microstructure analysis. For the SEM observation and EBSD analysis all samples deformed in 400 \u0026deg;C were selected due to their distinctive curve shape as well as the fact that samples deformed in this temperature were rarely described in literature. For the comparison, samples from the other end of the tests spectrum\u0026nbsp; was also analysed: 800 \u0026deg;C for the minimum and maximum strain rates (0.01 s\u003csup\u003e-1\u003c/sup\u003e and 10 s\u003csup\u003e-1\u003c/sup\u003e). For the reference, original, undeformed sample was also observed. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOriginal sample microstructure observation revealed equiaxed grains. (Fig 3a). The EBSD analysis performed for the original sample indicates existence of the grains of homogenous size. The average size of the grain was detected as 6.06 \u0026micro;m and median size is 5.22 \u0026micro;m (fig. 4a).\u003c/p\u003e\n\u003cp\u003eAt the 400 \u0026deg;C temperature and the low strain rate (0.01/s), we can observe grain size reduction and deformation. The grains are elongated.\u0026nbsp; Significant amount of grains were fragmented, and the average and median grain size were also lower being equal respectively 4.93 \u0026micro;m and 3.79 \u0026micro;m (fig. 3b).\u003c/p\u003e\n\u003cp\u003eIn the case of 400 \u0026deg;C and 0.1/s sample we can see very significant grain size reduction. The recorded average and median grain sizes were equal 2.62 \u0026micro;m and 1.61 \u0026micro;m respectively (fig 3c, 4b).\u003c/p\u003e\n\u003cp\u003eWe can observe almost identical grain distribution for the 400 \u0026deg;C, 1/s sample as in the previous one. But this value could be even smaller because we could observe significant amount of unresolved analysis points what is related to stronger plastic deformation and higher density of defects in the material. The higher strain rate does not seem to significantly improve grain fragmentation but the grains looks more deformed and elongated. Between the elongated grains we could observe fragmentation of the grains which is below the resolution of the system (fig. 3d).\u0026nbsp; Average grain size equals 2.1 \u0026micro;m, while median grain size is 1.43 \u0026micro;m (fig. 4c).\u003c/p\u003e\n\u003cp\u003eFor the highest strain rate in 400 \u0026deg;C we recorded unusual grain distribution. During this thermoplastic test DRX occurred due to combination of temperature and high strain rate causing grain growth. Grain size distribution is similar to the original sample apart from the larger amount of small sized grains. The grain size distribution looks more like a bimodal. We could observe significant number of bigger grains with visible slip bands, and high number of small grains between the bigger ones (fig. 3e). Avg. grain size is 5.04 \u0026micro;m while median size is 3.61 \u0026micro;m (fig. 4d).\u003c/p\u003e\n\u003cp\u003eIn the case of the samples deformed in highest temperature i.e.: 800 \u0026deg;C we clearly can see that the high temperature caused grain growth, which effect was not eliminated even by high strain rate.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor the 800 \u0026deg;C, 0.01/s sample we can see a significant increase in the grain size, with the average size: 15.5 \u0026micro;m and median being 13.5 \u0026micro;m (fig. 5a, 6a).\u003c/p\u003e\n\u003cp\u003eFor the 10/s strain rate we still could observe an increase in the grain size, although not such drastic as in previous example. The registered values of\u0026nbsp; average and median grain size are: 11.1 \u0026micro;m and 8.94 \u0026micro;m (fig 5b, 6b).\u003c/p\u003e\n\u003cp\u003eComparative compression strength tests were made in order to monitor changes in material strength. Tests were performed on the INSTRON 8802 machine with strain rate equal to 1/min. The samples were deformed until 250 kN of load was reached. Specimens were cut from the samples previously compressed during thermoplastic experiment. Their dimensions were 12 mm in diameter and 5.5 mm in height. The changes in the sample length during compression were monitored with use of the extensometer. The stress-strain curves registered as a result of the measurement were used to determine the yield point of each sample.\u003c/p\u003e\n\u003cp\u003eOriginal material during compression in the room temperature yields at around 900 MPa (fig. 7). Similar response of the material was reported by Soares and Hokka [35], where alpha titanium compressed with the strain rate 1/s yielded at 700-800 MPa.\u003c/p\u003e\n\u003cp\u003eIn this case, for the specimens previously deformed under 400\u0026deg; C, yield point is around 600 MPa for the 10/s strain rate and 1380 MPa for the 0.01/s strain rate indicating strengthening of the material (fig. 7a). For both 0.1/s and 1/s material yields around 700 MPa (fig. 7a). In the case of \u0026ldquo;500 \u0026deg;C\u0026rdquo; set we can observe slight increase of the yield point in relation to the strain rate. For 0.01/s we can report 913 MPa, for 0.1/s \u0026ndash; 980 MPa, for 1/s 1100 MPa is noted, and for 10/s, 1250 MPa is reported (fig. 7b).\u0026nbsp; In the \u0026ldquo;600\u0026deg; C\u0026rdquo; set, yield point can be observed at around 800-850 MPa for all but 10/s strain rates. This one yields at 1000 MPa (fig. 7c). Specimens deformed at the 700\u0026deg; C show similar behaviour as those deformed at 600\u0026deg; C with the only difference in the values of the Yield point. For the 10/s sample it is around 1000 MPa, for the rest \u0026ndash; 600-800 MPa (fig. 7d). Interestingly, for the \u0026ldquo;800\u0026deg;C\u0026rdquo; set we have 800 MPa yield point for all samples (fig. 7e). It is worth noticing changes of the work hardening behaviour of the specimens.\u0026nbsp; With an increase of the temperature, the yield point becomes less obvious and material deforms more plastically. The influence of the strain rate is also suppressed by the temperature influence (fig. 7d, e).\u0026nbsp; This can be attributed to the behaviour of dislocation slip in samples deformed at higher temperatures [36].\u003c/p\u003e\n\u003cp\u003eHardness measurements were performed on a HV 0.2 scale. The load was equal 1.961 N with the hold time \u0026nbsp;equal 5 seconds. Six measurements were taken on each sample to provide statistically reliable results. The mean hardness HV 0.2 for undeformed Grade 2 titanium is 200.4 \u0026ndash; which is characteristic for this material [37]. The mean hardness values are presented alongside the yield points of the deformed titanium (fig. 8). In all cases an improvement in hardness is visible. For the samples deformed in 400 \u0026deg;C we can observe an average increase by 65 points, for 500 \u0026deg;C by 74 points, for 600 \u0026deg;C - 53 points, 700 \u0026deg;C - 43 points, and for 800 \u0026deg;C \u0026ndash; 36 points. The most significant hardness increase was observed for temperature range 400 \u0026ndash; 600 \u0026deg;C. For the highest temperatures the grain growth overcame the process of grain fragmentation, causing an increase in grain size and thus lowering hardness values [38]. Lower hardness values could also be attributed to dislocation systems created at high temperatures [36], [39].\u003c/p\u003e\n\u003cp\u003eOne of the significant factors influencing the hardness of the titanium is grain size. In the case of titanium deformed at 400 \u0026deg;C significant grain reduction has been achieved. For the 800 \u0026deg;C an increase in hardness was also registered, but not as noticeable as for lower temperature (fig. 9).\u0026nbsp; This observations clearly indicate strong influence of multiple factors on the acquired results: dislocation density, microstructure texture, grain orientation etc. [40].\u003c/p\u003e"},{"header":"4. Summary and conclusions","content":"\u003cp\u003eThermoplastic deformation of the pure titanium has been performed successfully, resulting in significant grain size reduction and meaningful changes in the material properties. The most desirable changes were noted for the deformation performed at 400 \u0026deg;C, with strain rates 0.1/s and 1/s. As indicated in previous report\u0026nbsp;[5], very desirable grain reduction was also achieved at 600 \u0026deg;C, so we can safely assume that temperature 500 \u0026deg;C is also viable for this process. The DRX was noted for the deformation at 400 \u0026deg;C and 10/s strain rate, causing grain growth. Thus, we can conclude that this strain rate is too high. Both 0.1/s and 1/s present good findings, however in the case of 1/s there is a lot of unindexed points, which indicates high dislocation density and high grain fragmentation, which in turn greatly improves fibroblast cells colonization\u0026nbsp;[41]\u0026ndash;[43].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe temperature 800 \u0026deg;C is definitely too high for the purpose of grain fragmentation. Stress-strain graphs, microstructure observations, EBSD analysis, and strength test indicate that grain growth due to high temperature suppresses grain fragmentation caused by high strain rates. The experimental results also indicate that 700 \u0026deg;C temperature might be undesirable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe observed an increase in hardness values for all cases in comparison to the original sample. The grain size however seems to be only one of the factors influencing this property. The literature studies point to the dislocation density as one of the most meaningful factors influencing hardness\u0026nbsp;[39]. The temperature seems to have an effect on the hardness, but strain rate influence seems to be negligible. Increase in hardness is beneficial from the biomedical point of view due to the improved resistance against wear and corrosion\u0026nbsp;[44], [45].\u003c/p\u003e\n\u003cp\u003eThis interesting findings not only highlight the viability of thermomechanical processing as a tool for grain fragmentation but also point at new research opportunities: there is necessity in determination how dislocation density, microstructure texture and grain orientation influence the hardness and plasticity of the titanium.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe dataset used and/or analysed during the current study will be made available by the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eN. Soro, L. Brassart, Y. Chen, M. Veidt, H. Attar, and M. S. 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Mater.\u003c/em\u003e, vol. 1, no. 1, pp. 30\u0026ndash;42, Jan. 2008, doi: 10.1016/j.jmbbm.2007.07.001.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Titanium, EBSD, microstructure, grain refinement, thermoplastic forming","lastPublishedDoi":"10.21203/rs.3.rs-3323590/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3323590/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Pure titanium due to its high corrosion resistance, low stiffness and good mechanical properties is commonly used in medicine for orthopaedic applications. However, its material properties can be further enhanced to better fulfil the role of the biocompatible material. The thermoplastic deformation in heightened temperature is proposed as a method for microstructure improvement. Titanium samples were compressed in different temperatures and strain rates in order to determine the best conditions for grain fragmentation – the main factor responsible for strength and hardness increase. The thermoplastic stress-strain curves were registered. Then microstructure observations and electron backscatter analysis were performed on the chosen samples. Finally, mechanical response of the previously deformed material was obtained in room temperature compression tests. A significant grain fragmentation was recorded for the material deformed in 400 °C, at 0.1/s and 1/s strain rates. Desirable results were also noticed for the deformation performed at 500-600 °C. However, high temperatures (700-800 °C) and strain rates (10/s) resulted in dynamic recrystallization, causing undesirable grain growth. An increase in hardness was observed in all cases, with higher values recorded in lower deformation temperatures. Room temperature compression tests revealed slight increase of ductility.","manuscriptTitle":"Thermoplastic compression is a technique of pure titanium microstructure enhancement for biomedical applications","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-09-12 14:43:12","doi":"10.21203/rs.3.rs-3323590/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4d3373fa-46c4-486c-9347-265c5af511ae","owner":[],"postedDate":"September 12th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":24480918,"name":"Biological sciences/Biotechnology"},{"id":24480919,"name":"Physical sciences/Materials science"}],"tags":[],"updatedAt":"2023-11-24T05:59:16+00:00","versionOfRecord":[],"versionCreatedAt":"2023-09-12 14:43:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3323590","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3323590","identity":"rs-3323590","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}